1. Field of the Invention
This invention relates to a continuous casting machine for metals and, more particularly, it pertains to improved apparatus for monitoring and sensing positions of rolls which provide a path of travel for a continuously cast strand of metal as it solidifies.
2. Description of the Prior Art
A conventional continuous casting machine is characterized by a liquid metal continuously poured into a water cooled open-ended mold from which a partially solidified middle strand issues and moves between a series of spaced rolls which engage opposite surfaces of the strand. The series of spaced rolls form a path of travel for the strand which generally extends vertically from the mold and then turns to a horizontal direction.
Heretofore each roll has been a single structure coextensive with the width of the metal strand the opposite ends of which roll are journally mounted. With repeated use of the casting machine the rolls gradually deviate from their original positions due to such conditions as bending, wear of the roll surface, and deterioration of the journal mounting. For this reason, it has been desirable to periodically monitor the condition of the rolls to determine the necessity of replacement. For that purpose, a so-called "sled" has been used for testing the gap between pairs of rolls, such as disclosed in U.S. Pat. No. 3,939,568, issued Feb. 24, 1976, entitled "Method and Apparatus for Locating Improperly Positioned or Bent Rolls" of which the inventors are Michael G. Gonos, Kenneth D. Ives, and Ronald S. Vranka. All previous roll gap measuring sleds use runners to apply loads to a position the road gap measuring sled in a cast line. Some of the runners apply a load of sufficient magnitude to lift the caster containment rolls to reduce or eliminate any bearing clearances that affect the accuracy of the measurement.
As the state of the art of continuous casing procedures has developed, casting speeds have increased and roll spacing has decreased which conditions have resulted in the replacement of single rolls with segmented rolls. The sleds used for measuring roll gaps between pairs of single rolls of the prior art have not been satisfactory for measuring gaps between pairs of segmented rolls. Segmented rolls are rolls comprised of two or three longitudinal roll sections.